Stop using cadmium paints


“WHAT! there is cadmium in cadmium red? ” exclaimed once a student when we talked about colors. Are you also one of those who are not aware that there are toxic colors. Cadmium is one of the most toxic heavy metals and it cannot be broken down. It is stored in the body and is found in most things we eat. It causes osteoporosis, kidney damage and increased cancer risk.

Cadmium in paint exists in the forms cadmium sulfide and Cadmium sulfoselenide but also as compounds with other metals. The colors have a color tone from lemon yellow to deep red, they are very pure, it is mainly this property that makes the color difficult to replace with other pigments. They have very high opacity, are very durable, and they are expensive.

I find them difficult to use in watercolor, the yellow colors are so opaque that green color mixtures become “thick” and difficult to handle, the red ones have no ability to mix in the violet direction, if you own a cadmium red, try to mix it with blue to create a violet, it is not possible, the result is just a brownish mud. The only possibility for fine mixtures with cadmium colors is with each other, yellow and red give good orange mixtures.

Why is a very toxic, difficult to handle and expensive paint with clear restrictions so popular? Personally, I think that most people who use cadmium paints have not considered this significantly, it is just out of old habit, or they have heard at some point that they should be good colors.

Swedish sewage treatment plants measure the cadmium content in the wastewater, it is striking that the cadmium content in the water is higher in the vicinity of art schools. Shouldn’t they learn how to handle cadmium paints? This is how to handle such colors according to Swedish sewage treatment plants:

  1. Thoroughly wipe pallets and brushes in cloths or kitchen paper, place them in a bag.
  2. Rinse off the remaining paint residue, brushes and other things with paint, in a jar of water, also wash the palette in the same jar of water.
  3. Let the rinsing water rest for a few days until the paint residues have sunk to the bottom, pour the “clean” water into the drain very carefully, avoid letting any part of the water with paint come in.
  4. Wipe the jar with rags or paper and put them in a waste bag.
  5. Take the garbage bag with all rags to a manned recycling center as hazardous waste. All empty tubes and paint cups must also be handled in this way.

There is no one who does that, I can promise. No person, anywhere in the world, has ever done this for the environment. It has never happened.

Did you know that:

  • Up to 45% of a cadmium paint in watercolor is pure cadmium.
  • In Swedish wastewater, and probably in all other countries as well, a significant part of cadmium comes from artist paints.
  • In the EU, more and more products with cadmium have been banned, but there is an exception for artist paint.
  • Sweden tried to get a ban on lead and cadmium paints in the EU, but the proposal fell in a decision from 2015.

So if you are one of those people who use cadmium paints just because you happen to own one, hand it in for destruction, and do not buy it again. There is no excuse for using a very toxic paint whose contents cannot be degraded and which have few or no artistic benefits.

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9 months ago

The best substitute for cadmium red may be PR 251. It was developed for the auto industry and has unusually large particles for an organic pigment. This improves its lightfastness.

Cadmium’s opacity and lower oil requirement for grinding are both benefits in oil painting. I think most of the resistance to losing cadmium’s will come from oil painters. Organic pigments typically require a lot more oil, giving them inferior opacity and making them questionable for underpainting. Oil painters should simply start disposing of the paints correctly. Few may be doing that but some professionals may be willing to start in order to keep them as options. In watercolors, cadmium paints aren’t needed.

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